Secretary of Homeland Security John Kelly said Thursday that construction for the proposed wall on the U.S.-Mexico border should begin by this summer.

Kelly appeared on Fox News alongside Attorney General Jeff Sessions and was asked by host Martha MacCallum about the border wall's status.

The DHS chief first said many reforms have been implemented and that illegal border crossings were down 70 percent in the past couple of months. He noted that Border Patrol personnel in the sector where the two Cabinet members were touring said the fencing in place there has been "remarkably effective in keeping down the amount of illegal movement across the two borders."

MacCallum then asked Kelly when construction of the wall will begin.

Kelly said that around 100 companies are beginning to put prototypes together for Homeland Security and that they would be reviewing them soon. He added that construction should begin by the summer.

"I think by late spring, early summer, we'll have some prototypes and then we'll be able to move forward by into the summer," Kelly said.

"We're going to get at it as quick as we can," he added.

Kelly also said the process of contracting with the federal government is too complicated and hampering the process.

Building a border wall was a major part of President Donald Trump's campaign.